U.S. patent number 11,438,749 [Application Number 17/405,635] was granted by the patent office on 2022-09-06 for acoustic apparatus and volume control method for acoustic apparatus.
This patent grant is currently assigned to KABUSHIKI KAISHA TOSHIBA, TOSHIBA ELECTRONIC DEVICES & STORAGE CORPORATION. The grantee listed for this patent is Kabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation. Invention is credited to Makoto Yamashita.
United States Patent |
11,438,749 |
Yamashita |
September 6, 2022 |
Acoustic apparatus and volume control method for acoustic
apparatus
Abstract
An acoustic apparatus according to each of the embodiments
includes a reception unit, an operation unit, and a control unit.
The reception unit is configured to receive a packet to which voice
data and a signal for azimuth estimate are added. The operation
unit is configured to operate a signal angle of the packet by using
the signal for azimuth estimate. The control unit is configured to
control information related to a sound image of the voice data
according to the signal angle.
Inventors: |
Yamashita; Makoto (Yokohama
Kanagawa, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Kabushiki Kaisha Toshiba
Toshiba Electronic Devices & Storage Corporation |
Tokyo
Tokyo |
N/A
N/A |
JP
JP |
|
|
Assignee: |
KABUSHIKI KAISHA TOSHIBA
(Tokyo, JP)
TOSHIBA ELECTRONIC DEVICES & STORAGE CORPORATION (Tokyo,
JP)
|
Family
ID: |
1000006545921 |
Appl.
No.: |
17/405,635 |
Filed: |
August 18, 2021 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20220078594 A1 |
Mar 10, 2022 |
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Foreign Application Priority Data
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Sep 9, 2020 [JP] |
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JP2020-151547 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
4/80 (20180201); H04W 84/18 (20130101) |
Current International
Class: |
H04W
4/80 (20180101); H04W 84/18 (20090101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2006-067468 |
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Mar 2006 |
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JP |
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2007-013407 |
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Jan 2007 |
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JP |
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2020-005024 |
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Jan 2020 |
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JP |
|
Primary Examiner: Bilodeau; David
Attorney, Agent or Firm: Allen & Overy LLP
Claims
What is claimed is:
1. An acoustic apparatus comprising: a reception unit configured to
receive a packet to which voice data and a signal for azimuth
estimate are added; an operation unit configured to operate a
signal angle of the packet by using the signal for azimuth
estimate; and a control unit configured to control information
related to a sound image of the voice data according to the signal
angle.
2. The acoustic apparatus according to claim 1, further comprising
a first speaker and a second speaker configured to output voice
based on the voice data, wherein the control unit controls
respective volume values of the first speaker and the second
speaker according to the signal angle.
3. The acoustic apparatus according to claim 2, wherein the control
unit controls the respective volume values of the first speaker and
the second speaker when the packet is received from the signal
angle within a predetermined range for at least a predetermined
period of time.
4. The acoustic apparatus according to claim 2, wherein the control
unit controls the respective volume values of the first speaker and
the second speaker according to loudness of the voice based on the
voice data.
5. The acoustic apparatus according to claim 2, wherein the control
unit controls voice output timing, a phase, and/or a voice spectrum
of each of the first speaker and the second speaker according to
the signal angle.
6. The acoustic apparatus according to claim 1, wherein the
operation unit operates the signal angle based on phase information
of the packet.
7. The acoustic apparatus according to claim 1, further comprising
one antenna, wherein the packet transmitted with switching among a
plurality of antennas is received by the one antenna.
8. The acoustic apparatus according to claim 1, further comprising
a plurality of antennas, wherein the packet transmitted from one
antenna is received while switching among the plurality of
antennas.
9. The acoustic apparatus according to claim 1, further comprising
a first plurality of antennas, wherein the packet transmitted from
a second plurality of antennas is received while switching among
the first plurality of antennas.
10. A volume control method for an acoustic apparatus comprising:
receiving a packet to which voice data and a signal for azimuth
estimate are added; operating a signal angle of the packet by using
the signal for azimuth estimate; and controlling information
related to a sound image of the voice data according to the signal
angle.
11. The volume control method for an acoustic apparatus according
to claim 10, wherein the acoustic apparatus further comprises a
first speaker and a second speaker configured to output voice based
on the voice data; and respective volume values of the first
speaker and the second speaker are controlled according to the
signal angle.
12. The volume control method for an acoustic apparatus according
to claim 11, wherein the respective volume values of the first
speaker and the second speaker are controlled when the packet is
received from the signal angle within a predetermined range for at
least a predetermined period of time.
13. The volume control method for an acoustic apparatus according
to claim 11, wherein the respective volume values of the first
speaker and the second speaker are controlled according to loudness
of the voice based on the voice data.
14. The volume control method for an acoustic apparatus according
to claim 11, wherein voice output timing, a phase, and/or a voice
spectrum of each of the first speaker and the second speaker are
controlled according to the signal angle.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority
from the prior Japanese Patent Application No. 2020-151547 filed on
Sep. 9, 2020; the entire contents of which are incorporated herein
by reference.
FIELD
Embodiments described herein relate generally to an acoustic
apparatus and a volume control method for an acoustic
apparatus.
BACKGROUND
Conventionally, playing back music on speakers or headphones by
audio streaming from a music playback app on a smartphone and the
like in a wireless manner through Bluetooth (registered trademark)
has been realized.
In recent years, the Bluetooth Low Energy (hereinafter referred to
as "BLE" for short) standard enabling further reduction of electric
power consumption than the conventional Bluetooth (registered
trademark) has been developed. Furthermore, a standard (Bluetooth
LE Audio) is being developed for realizing, by BLE, the function of
streaming audio playback of the conventional Bluetooth. The
standard has a broadcast audio function with which voice is
transmitted from one transmission device to a plurality of
reception devices.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing a configuration of a communication
system of a first embodiment;
FIG. 2 is a diagram showing an example of a configuration of a
transmission packet;
FIG. 3 is a diagram showing an example of a flow of transmission of
a transmission packet from an audio transmission device to an audio
reception device;
FIG. 4 is a block diagram showing a configuration of the audio
transmission device;
FIG. 5 is a block diagram showing a configuration of the audio
reception device;
FIG. 6 is a diagram showing a positional relationship between the
audio transmission device and the audio reception device;
FIG. 7 is a diagram showing a relationship between a transmission
angle and respective volume values of left-side and right-side
speakers;
FIG. 8 is a flow chart showing an example of transmission
processing of the transmission packet in the audio transmission
device;
FIG. 9 is a flow chart showing an example of volume control
processing in the audio reception device;
FIG. 10 is a flow chart showing another example of the volume
control processing in the audio reception device;
FIG. 11 is a flow chart showing yet another example of the volume
control processing in the audio reception device;
FIG. 12 is a diagram showing a relationship between a transmission
angle of finer granularity and respective volume values of the
left-side and right-side speakers;
FIG. 13 is a diagram showing a relationship between a transmission
angle and respective volume values of left-side and right-side
speakers when loudness of a lecturer's voice is greater than or
equal to a first threshold; and
FIG. 14 is a diagram showing a configuration of a communication
system of a second embodiment.
DETAILED DESCRIPTION
An acoustic apparatus according to each of the embodiments includes
a reception unit, an operation unit, and a control unit. The
reception unit is configured to receive a packet to which voice
data and a signal for azimuth estimate are added. The operation
unit is configured to operate a signal angle of the packet by using
the signal for azimuth estimate. The control unit is configured to
control information related to a sound image of the voice data
according to the signal angle.
Hereinafter, the embodiments are described in detail with reference
to the drawings.
First Embodiment
FIG. 1 is a diagram showing a configuration of a communication
system of a first embodiment.
As shown in FIG. 1, a communication system 1 is configured to
include an audio transmission device 10 and an audio reception
device 20, and carries out wireless communication between the audio
transmission device 10 and the audio reception device 20. Note that
the standard later than Bluetooth 5.1 is used as the wireless
communication method in the present embodiment.
The audio transmission device 10 is provided with a plurality of
antennas 11a, 11b, 11c, and 11d. The audio reception device 20 is
provided with one antenna 21. Note that although the audio
transmission device 10 is provided with the four antennas 11a to
11d linearly arranged at regular intervals in the example shown in
FIG. 1, the present embodiment is not limited to such a
configuration and only required to be provided with at least two
antennas.
The audio transmission device 10 transmits a transmission packet P,
which contains audio streaming data (voice data) and a CTE
(constant tone extension) to which a signal for azimuth estimate is
added, to the audio reception device 20 while switching among the
plurality of antennas 11a to 11d.
The audio reception device 20 as the acoustic apparatus receives
the transmission packet P containing the CTE transmitted from the
audio transmission device 10, and plays back voice based on the
audio streaming data. The audio reception device 20 calculates a
signal angle of the transmission packet P transmitted from the
audio transmission device 10 on the basis of the signal for azimuth
estimate added to the CTE, and controls information related to a
sound image according to the signal angle. The signal angle means:
a transmission angle .theta. being a direction in which the audio
reception device 20 is positioned with respect to the audio
transmission device 10; and a reception angle being a direction in
which the audio transmission device 10 is positioned with respect
to the audio reception device 20. In the first embodiment, the
transmission angle is used as the signal angle.
The audio reception device 20 of the first embodiment calculates
the transmission angle .theta. by the AoD (angle of departure)
method, which allows azimuth estimate by receiving with the one
antenna 21 the transmission packet P transmitted while switching
among the plurality of antennas 11a to 11d of the audio
transmission device 10. As described later in detail, the audio
reception device 20 is embedded in, for example, headphones, and
controls respective volume values of left-side and right-side
speakers (first and second speakers) according to the transmission
angle .theta..
FIG. 2 is a diagram showing an example of a configuration of the
transmission packet.
The transmission packet P includes: a preamble 31, an
access-address 32, a PDU (protocol data unit) 33, a CRC (cyclic
redundancy code) 34, and a CTE (constant tone extension) 35.
The preamble 31 is a field in which data for determining the head
of the packet is stored. The access-address 32 is a field in which
data allowing a reception device to determine whether the packet is
addressed to the reception device is stored. The PDU 33 is a field
in which transmission data such as audio streaming data is stored.
The CRC 34 is a field in which an error correction code is stored.
The CTE 35 is a field in which a signal for azimuth estimate is
stored.
The audio transmission device 10 adds audio streaming data to the
PCU 33 and the signal for azimuth estimate to the CTE 35, and
transmits the packet to the audio reception device 20. More
specifically, the audio transmission device 10 measures a phase of
radio wave upon transmission with switching among the respective
antennas 11a to 11d using the IQ (in-phase and quadrature)
sampling, adds a value thus measured to the CTE 35, and transmits
the packet to the audio reception device 20.
FIG. 3 is a diagram showing an example of a flow of transmission of
the transmission packet from the audio transmission device to the
audio reception device.
The audio transmission device 10 transmits the transmission packet
P to the audio reception device 20 with sequentially switching
among the plurality of antennas 11a to 11d. More specifically, as
shown in FIG. 3, the transmission packet P is transmitted to the
audio reception device 20, with the antennas 11a to 11d being
switched in an order of: the antenna 11a; the antenna 11b; the
antenna 11c; the antenna 11d; the antenna 11a; and so on.
The audio reception device 20 receives via the antenna 21 the
transmission packet P sequentially transmitted from the antennas
11a to 11d of the audio transmission device 10. Note that although
the transmission packet P is transmitted in the order of: the
antenna 11a; the antenna 11b; the antenna 11c; the antenna 11d; the
antenna 11a; and so on in the example shown in FIG. 3, the order of
transmission of the transmission packet P is not limited to the
order of: the antenna 11a; the antenna 11b; the antenna 11c; the
antenna 11d; the antenna 11a; and so on, and may be in a different
order.
FIG. 4 is a block diagram showing a configuration of the audio
transmission device.
As shown in FIG. 4, the audio transmission device 10 is configured
to include, in addition to the aforementioned plurality of antennas
11a to 11d, a sound collection unit 12, an AD conversion unit 13, a
control unit 14, a program storage unit 15, and a communication
unit 16.
The control unit 14 is a micro control unit (hereinafter referred
to as "MCU") configured to control the AD conversion unit 13, the
program storage unit 15, and the communication unit 16. The control
unit 14 executes a program stored in the program storage unit 15 to
communicate with the audio reception device 20, which is a
communication counterpart, via the communication unit 16, and
controls the audio transmission device 10 as a whole.
The sound collection unit 12 collects sound around the audio
transmission device 10, for example a lecturer's voice. The voice
data collected by the sound collection unit 12 is inputted to the
AD conversion unit 13. The AD conversion unit 13 converts the voice
data inputted, from an analog signal to a digital signal, and
outputs the digital signal to the control unit 14.
The control unit 14 generates audio streaming data from the voice
data of the digital signal inputted from the AD conversion unit 13.
The control unit 14 also measures the phase of radio wave upon
transmission with switching among the respective antennas 11a to
11d. The control unit 14: adds the audio streaming data to the PDU
33; generates the transmission packet P in which the value thus
measured, which is a signal for azimuth estimate, is added to the
CTE 35; and outputs the transmission packet P to the communication
unit 16.
The communication unit 16 transmits the transmission packet P while
switching among the antennas 11a to 11d, on the basis of the
control by the control unit 14.
FIG. 5 is a block diagram showing a configuration of the audio
reception device.
As shown in FIG. 5, the audio reception device 20 is configured to
include, in addition to the aforementioned antenna 21, a
communication unit 22, a control unit 23, a program storage unit
24, a DA conversion unit 25, a left-side speaker 26a, and a
right-side speaker 26b.
The control unit 23 is an MCU configured to control the
communication unit 22, the program storage unit 24, and the DA
conversion unit 25. The control unit 23 executes a program stored
in the program storage unit 24 to communicate with the audio
transmission device 10, which is a communication counterpart, via
the communication unit 22, and controls the audio reception device
20 as a whole.
The communication unit 22 configuring the reception unit receives
via the antenna 21 the transmission packet P transmitted from the
audio transmission device 10, and outputs the transmission packet P
to the control unit 23.
The control unit 23 outputs the audio streaming data in the PDU 33
of the transmission packet P to the DA conversion unit 25. The
control unit 23 configuring the operation unit operates the
transmission angle .theta. at which the transmission packet P was
transmitted, on the basis of the signal for azimuth estimate in the
CTE 35 of the transmission packet P. The control unit 23 controls
the respective volume values of the left-side speaker 26a and the
right-side speaker 26b according to the transmission angle .theta.
thus operated.
The DA conversion unit 25 converts the audio streaming data from a
digital signal to an analog signal, and outputs the analog signal
to the left-side speaker 26a and the right-side speaker 26b. The DA
conversion unit 25 is capable of changing the volume value
individually for the left-side speaker 26a and the right-side
speaker 26b, through control from the control unit 23.
FIG. 6 is a diagram showing a positional relationship between the
audio transmission device and the audio reception device. FIG. 7 is
a diagram showing a relationship between a transmission angle and
respective volume values of left-side and right-side speakers; In
the diagram shown in FIG. 6, for example voice of a lecturer on a
stage is captured via a microphone 40 and outputted from headphones
worn by a listener. The lecturer can speak while looking in a
vertically downward direction in FIG. 6, and move in a horizontal
direction in FIG. 6 between a position A1 and a position A3 on the
stage. The listener looks in a vertically upward direction in FIG.
6, and faces the lecturer when the lecturer is in a position A2 at
the center of the stage.
As shown in FIG. 6, the audio transmission device 10 is embedded
in, for example, the microphone 40 used by the lecturer, and
transmits the transmission packet P containing the audio streaming
data, the signal for azimuth estimate, and the like.
The audio reception device 20 is embedded in, for example,
headphones 50 used by a user such as the listener, determines the
transmission angle .theta. of the transmission packet P on the
basis of the signal for azimuth estimate, and plays back the audio
streaming data through control of the respective volume values of
the left-side speaker 26a and the right-side speaker 26b according
to the transmission angle .theta. thus determined.
When the lecturer with the microphone 40 is in the position A1, the
transmission angle .theta. between the microphone 40 and the
headphones 50 is represented by .theta.1. When the lecturer with
the microphone 40 is in the position A2, the transmission angle
.theta. between the microphone 40 and the headphones 50 is
represented by .theta.2. When the lecturer with the microphone 40
is in the position A3, the transmission angle .theta. between the
microphone 40 and the headphones 50 is represented by .theta.3.
Note that for the transmission angle .theta. of the transmission
packet P, the horizontally rightward direction in FIG. 6 is a
reference of 0 degrees, and the clockwise direction is the positive
direction of the angle.
When the transmission angle .theta.1 is 30 degrees, the
transmission angle .theta.1 falls within a range of at least 0
degrees and smaller than 60 degrees. The control unit 23 sets the
volume value for the left-side speaker 26a to 100%, and the volume
value for the right-side speaker 26b to 50% on the basis of the
relationship shown in FIG. 7. Due to the volume value for the
left-side speaker 26a being set greater than the volume value for
the right-side speaker 26b, the headphones 50 of the user sound as
if the lecturer is speaking from the left side.
When the transmission angle .theta.2 is 90 degrees, the
transmission angle .theta.2 falls within a range of at least 60
degrees and smaller than 120 degrees. The control unit 23 sets the
volume value for the left-side speaker 26a and the volume value for
the right-side speaker 26b to 100% on the basis of the relationship
shown in FIG. 7. Due to the same volume value being set for the
left-side speaker 26a and the right-side speaker 26b, the
headphones 50 of the user sound as if the lecturer is speaking from
the center.
When the transmission angle .theta.3 is 150 degrees, the
transmission angle .theta.3 falls within a range of at least 120
degrees and not more than 180 degrees. The control unit 23 sets the
volume value for the left-side speaker 26a to 50%, and the volume
value for the right-side speaker 26b to 100% on the basis of the
relationship shown in FIG. 7. Due to the volume value for the
right-side speaker 26b being set greater than the volume value for
the left-side speaker 26a, the headphones 50 of the user sound as
if the lecturer is speaking from the right side.
FIG. 8 is a flow chart showing an example of transmission
processing of the transmission packet in the audio transmission
device. Note that the transmission processing shown in FIG. 8 is
carried out by the control unit 14 of the audio transmission device
10.
First, the control unit 14 generates the signal for azimuth
estimate required for transmission angle operation (S1). Next, the
control unit 14 generates the audio streaming data (S2).
Thereafter, the control unit 14 generates the transmission packet P
containing the signal for azimuth estimate and the audio streaming
data, and transmits the transmission packet P while switching among
the antennas 11a to 11d (S3).
The control unit 14 determines whether the communication has been
terminated or not (S4). When it is determined that the
communication has not been terminated (S4: NO), the control unit 14
returns the processing to S1 and repeats the same processing. On
the other hand, when it is determined that the communication has
been terminated (S4: YES), the control unit 14 terminates the
processing.
FIG. 9 is a flow chart showing an example of volume control
processing in the audio reception device. Note that the volume
control processing shown in FIG. 9 is carried out by the control
unit 23 of the audio reception device 20.
The control unit 23 receives via the antenna 21 the transmission
packet P transmitted from the antennas 11a to 11d (S11). The
control unit 23 carries out the operation processing of the
transmission angle .theta. on the basis of the phase information of
the transmission packet P transmitted from the antennas 11a to 11d
(S12). The control unit 23 determines what the transmission angle
.theta. is (S13).
When the transmission angle .theta. is determined to be at least 0
degrees and smaller than 60 degrees, the control unit 23 causes the
left-side speaker 26a and the right-side speaker 26b to output the
voice with the output of the left-side speaker 26a being set to
100% and the output of the right-side speaker 26b being set to 50%
(S14).
When the transmission angle .theta. is determined to be at least 60
degrees and smaller than 120 degrees, the control unit 23 causes
the left-side speaker 26a and the right-side speaker 26b to output
the voice with the output of the left-side speaker 26a being set to
100% and the output of the right-side speaker 26b being set to 100%
(S15).
When the transmission angle .theta. is determined to be at least
120 degrees and not more than 180 degrees, the control unit 23
causes the left-side speaker 26a and the right-side speaker 26b to
output the voice with the output of the left-side speaker 26a being
set to 50% and the output of the right-side speaker 26b being set
to 100% (S16).
After carrying out the processing of S14, S15, or S16, the control
unit 23 determines whether the communication has been terminated or
not (S17). When it is determined that the communication has not
been terminated, the control unit 23 returns the processing to S11
and repeats the same processing. On the other hand, when it is
determined that the communication has been terminated, the control
unit 23 terminates the processing.
Due to the aforementioned process, the audio reception device 20
can control the respective volume values of the left-side speaker
26a and the right-side speaker 26b according to the transmission
angle .theta. of the transmission packet P.
In the related art, for example even in a case in which the
lecturer moves right and left on a stage, the headphones worn on
the user's ears played back audio with equal volume value for the
left-side speaker and the right-side speaker. Therefore, the
conventional audio reception device has not been able to carry out
audio playback with presence in such a manner to make the listener
perceive as if he/she is listening directly to a live voice, by
outputting sound from the right side when the lecturer moves to the
right side on the stage, and outputting sound from the left side
when the lecturer moves to the left side on the stage.
On the other hand, the audio reception device 20 of the present
embodiment sets the volume value of the right-side speaker 26b
greater than the volume value of the left-side speaker 26a when the
lecturer moves to the right side on the stage, and sets the volume
value of the left-side speaker 26a greater than the volume value of
the right-side speaker 26b when the lecturer moves to the left side
on the stage, for example. Consequently, the audio reception device
20 is able to carry out audio playback in such a manner to make the
user using the headphones 50 perceive as if he/she is listening
directly to a live voice. Therefore, the audio reception device 20
configuring the acoustic apparatus according to the present
embodiment enables audio playback with presence.
Various modifications shown in FIGS. 10 to 13 may be made to the
above-described embodiment. In the above-described embodiment, the
respective volume values of the left-side speaker 26a and the
right-side speaker 26b are controlled in the cases of the
transmission angle .theta. being: at least 0 degrees and smaller
than 60 degrees; at least 60 degrees and smaller than 120 degrees;
and at least 120 degrees and not more than 180 degrees. In other
words, the above-described embodiment supposes that the
transmission packet P is transmitted from a front side of the user
using the headphones 50. However, it may also be envisaged that the
transmission packet P is transmitted from a rear side of the user,
that is at the transmission angle .theta. between 0 degrees and
-180 degrees.
Given this, the control unit 23 may control the respective volume
values of the left-side speaker 26a and the right-side speaker 26b
in the cases of the transmission angle .theta. being: smaller than
0 degrees and at least -60 degrees; smaller than -60 degrees and at
least -120 degrees; and smaller than -120 degree and at least -180
degrees.
FIG. 10 is a flow chart showing another example of the volume
control processing in the audio reception device. Note that in FIG.
10 the processing similar to the processing shown in FIG. 9 is
denoted by the same reference symbol and description of such
processing is omitted.
The control unit 23 carries out the operation processing of the
transmission angle .theta. in the processing of S12, and then
determines what the transmission angle .theta. is (S21).
When the transmission angle .theta. is determined to be smaller
than 0 degrees and at least -60 degrees, the control unit 23
advances the processing to S14 and causes the left-side speaker 26a
and the right-side speaker 26b to output the voice with the output
of the left-side speaker 26a being set to 100% and the output of
the right-side speaker 26b being set to 50%.
When the transmission angle .theta. is determined to be smaller
than -60 degrees and at least -120 degrees, the control unit 23
advances the processing to S15 and causes the left-side speaker 26a
and the right-side speaker 26b to output the voice with the output
of the left-side speaker 26a being set to 100% and the output of
the right-side speaker 26b being set 100%.
When the transmission angle .theta. is determined to be smaller
than -120 degrees and at least -180 degrees, the control unit 23
advances the processing to S16 and causes the left-side speaker 26a
and the right-side speaker 26b to output the voice with the output
of the left-side speaker 26a being set to 50% and the output of the
right-side speaker 26b being set to 100%. Other processing is
similar to the processing shown in FIG. 9.
In the above-described embodiment, for example when the lecturer
frequently moves back and forth in the vicinity of the position at
60 degrees, the volume value for the left-side speaker 26a of the
headphones 50 is frequently switched between 50% and 100%, making
it difficult for the user using the headphones 50 to listen to the
voice.
Given this, the control unit 23 controls the respective volume
values of the left-side speaker 26a and the right-side speaker 26b
when the transmission packet P is transmitted from the same angle
range for at least a predetermined period of time. In other words,
the control unit 23 measures a period of time during which the
transmission angle .theta. falls within a certain angle range (0 to
60 degrees, 60 to 120 degrees, or 120 to 180 degrees) by means of,
for example, an internal clock of the control unit 23. When the
control unit 23 determines that the measured time period has
exceeded the predetermined period of time, the control unit 23
changes the respective volume values of the left-side speaker 26a
and the right-side speaker 26b. Such a configuration can prevent
the volume value of at least one of the left-side speaker 26a or
the right-side speaker 26b from being frequently switched.
FIG. 11 is a flow chart showing yet another example of the volume
control processing in the audio reception device. Note that in FIG.
11 the processing similar to the processing shown in FIG. 9 is
denoted by the same reference symbol and description of such
processing is omitted.
The control unit 23 carries out the operation processing of the
transmission angle .theta. in the processing of S12, and then
determines what the transmission angle .theta. is and whether or
not the transmission angle .theta. is in the same angle range for
the predetermined period of time (S31).
When the transmission angle .theta. is determined to be at least 0
degrees and smaller than 60 degrees and in the same angle range for
the predetermined period of time, the control unit 23 advances the
processing to S14 and causes the left-side speaker 26a and the
right-side speaker 26b to output the voice with the output of the
left-side speaker 26a being set to 100% and the output of the
right-side speaker 26b being set to 50%.
When the transmission angle .theta. is determined to be at least 60
degrees and smaller than 120 degrees and in the same angle range
for the predetermined period of time, the control unit 23 advances
the processing to S15 and causes the left-side speaker 26a and the
right-side speaker 26b to output the voice with the output of the
left-side speaker 26a being set to 100% and the output of the
right-side speaker 26b being set 100%.
When the transmission angle .theta. is determined to be at least
120 degrees and not more than 180 degrees and in the same angle
range for the predetermined period of time, the control unit 23
advances the processing to S16 and causes the left-side speaker 26a
and the right-side speaker 26b to output the voice with the output
of the left-side speaker 26a being set to 50% and the output of the
right-side speaker 26b being set to 100%.
Although not illustrated, when the transmission angle .theta. is
determined not to be in the same angle range for the predetermined
period of time, the control unit 23 returns the processing to S11
and repeats the same processing.
In the above-described embodiment, the control unit 23 changes the
respective volume values of the left-side speaker 26a and the
right-side speaker 26b at every 60 degrees of the transmission
angle .theta.. Alternatively, the control unit 23 may also change
the respective volume values of the left-side speaker 26a and the
right-side speaker 26b with finer granularity, for example at every
10 degrees or every 20 degrees of the transmission angle
.theta..
FIG. 12 is a diagram showing a relationship between a transmission
angle of finer granularity and respective volume values of the
left-side and right-side speakers; When the transmission angle
.theta. is at least 0 degrees and smaller than 20 degrees, the
control unit 23 sets the volume value for the left-side speaker 26a
to 100%, and the volume value for the right-side speaker 26b to 60%
on the basis of the relationship shown in FIG. 12.
When the transmission angle .theta. is at least 20 degrees and
smaller than 40 degrees, the control unit 23 sets the volume value
for the left-side speaker 26a to 100%, and the volume value for the
right-side speaker 26b to 70% on the basis of the relationship
shown in FIG. 12.
When the transmission angle .theta. is at least 40 degrees and
smaller than 60 degrees, the control unit 23 sets the volume value
for the left-side speaker 26a to 100%, and the volume value for the
right-side speaker 26b to 80% on the basis of the relationship
shown in FIG. 12.
When the transmission angle .theta. is at least 60 degrees and
smaller than 80 degrees, the control unit 23 sets the volume value
for the left-side speaker 26a to 100%, and the volume value for
right-side speaker 26b to 90% on the basis of the relationship
shown in FIG. 12.
When the transmission angle .theta. is at least 80 degrees and
smaller than 100 degrees, the control unit 23 sets the volume value
for the left-side speaker 26a to 100%, and the volume value for the
right-side speaker 26b to 100% on the basis of the relationship
shown in FIG. 12.
When the transmission angle .theta. is at least 100 degrees and
smaller than 120 degrees, the control unit 23 sets the volume value
for the left-side speaker 26a to 90%, and the volume value for the
right-side speaker 26b to 100% on the basis of the relationship
shown in FIG. 12.
When the transmission angle .theta. is at least 120 degrees and
smaller than 140 degrees, the control unit 23 sets the volume value
for the left-side speaker 26a to 80%, and the volume value for the
right-side speaker 26b to 100% on the basis of the relationship
shown in FIG. 12.
When the transmission angle .theta. is at least 140 degrees and
smaller than 160 degrees, the control unit 23 sets the volume value
for the left-side speaker 26a to 70%, and the volume value for the
right-side speaker 26b to 100% on the basis of the relationship
shown in FIG. 12.
When the transmission angle .theta. is at least 160 degrees and
smaller than 180 degrees, the control unit 23 sets the volume value
for the left-side speaker 26a to 60%, and the volume value for the
right-side speaker 26b to 100% on the basis of the relationship
shown in FIG. 12.
Furthermore, the control unit 23 may also change the granularity
according to a size of a venue. The size of the venue is determined
by, for example, the control unit 23 figuring out an approximate
distance value on the basis of signal intensity and then comparing
magnitude with a reference distance. For example, the control unit
23 employs finer granularity for a venue greater in size and
employs coarser granularity for a venue smaller in size. By
employing finer granularity in the case of the larger venue, a
problem of the respective volume values of the left-side and
right-side speakers being not readily changeable due to a small
change in the transmission angle when the lecturer moves on a
distant stage, can be solved. Alternatively, for example, coarser
granularity may be employed for a venue greater in size and finer
granularity may be employed for a venue smaller in size. In a
smaller venue, since a distance between a listener and a stage is
small, the transmission angle is likely to be largely changed when
the lecturer moves in the horizontal direction in FIG. 6. By
employing finer granularity in the case of the smaller venue, the
change in the position of the lecturer (transmission angle) can be
reflected more precisely to the respective volume values of the
left-side and right-side speakers.
When the audio transmission device is in the vicinity of the center
of the stage, that is when the transmission angle is around 90
degrees, the change in the transmission angle is great with respect
to the moving distance of the lecturer. The granularity of the
transmission angle may be set finer when the transmission angle is
closer to 90 degrees, and coarser when the transmission angle is
closer to 0 degrees or 180 degrees.
The control unit 23 may also change the respective volume values of
the left-side speaker 26a and the right-side speaker 26b according
to loudness of the lecturer's voice, that is loudness of the voice
based on the audio streaming data. In this case, for example with a
first threshold value being defined, the control unit 23 changes
the volume values based on the table shown in FIG. 7 when the
loudness of the lecturer's voice is smaller than the first
threshold value, and changes the volume values based on the table
shown in FIG. 13, in which volume values are smaller than the
volume values in the table shown in FIG. 7, when the loudness of
the lecturer's voice is greater than or equal to the first
threshold value. FIG. 13 is a diagram showing a relationship
between a transmission angle and respective volume values of
left-side and right-side speakers when loudness of a lecturer's
voice is greater than or equal to a first threshold.
In a case in which the audio transmission device 10 includes three
or more antennas, the antennas may be configured to be arranged: in
two directions at regular intervals; or two-dimensionally in a
circular manner at regular intervals. In this case, the sound image
can be adjusted on the basis of a biaxial signal angle (azimuth
angle and elevation angle), whereby audio playback with more
presence can be carried out even in a case in which the lecturer
(transmission side) talks on a high stage for example.
The respective volume values of the left-side speaker 26a and the
right-side speaker 26b have been exemplified as a component of the
sound image adjusted by the audio reception device 20. However, the
component of the sound image is not limited to the volume value.
The sound image can also be adjusted through: increasing sound
pressure or advancing output timing of the voice output from the
speaker closer to the audio transmission device 10 compared to the
voice output from the other speaker; adjusting the phase; adjusting
the sound spectrum; and the like, on the basis of the transmission
angle .theta..
Second Embodiment
Next, the second embodiment is described.
FIG. 14 is a diagram showing a configuration of a communication
system of the second embodiment.
As shown in FIG. 14, a communication system 1A is provided with an
audio transmission device 10A and an audio reception device 20A.
The audio transmission device 10A is provided with one antenna 11.
The audio reception device 20A is provided with a plurality of
antennas 21a, 21b, 21c, and 21d. Note that although the audio
reception device 20A is provided with the four antennas 21a to 21d
in the example shown in FIG. 10, the present embodiment is not
limited to such a configuration and only required to be provided
with at least two antennas.
The audio transmission device 10A transmits a transmission packet P
containing audio streaming data to the audio reception device
20A.
The audio reception device 20A receives, with sequential switching
among the antennas 21a to 21d, the transmission packet P
transmitted from the audio transmission device 10A, and plays back
voice based on the audio streaming data. The audio reception device
20A calculates a reception angle .theta.A of the transmission
packet P on the basis of a difference of route upon reception, and
controls information related to a sound image according to the
reception angle .theta.A.
As described above, the audio reception device 20A of the second
embodiment is of the AoA (angle of arrival) method, by which the
transmission packet P transmitted from the one antenna 11 of the
audio transmission device 10A is received with switching among the
plurality of antennas 21a to 21d, and azimuth estimate is carried
out.
The internal configurations of the audio transmission device 10A
and the audio reception device 20A are different from the internal
configurations of the audio transmission device 10 and the audio
reception device 20 of the first embodiment in that the control
unit 23A of the audio reception device 20A receives the
transmission packet P with switching among the plurality of
antennas and calculates the reception angle .theta.A. Note that as
shown in FIG. 6, when the lecturer and the listener are oriented in
the vertical direction in FIG. 6, the transmission angle and the
reception angle are of the same value. In the second embodiment,
the respective volume values of the left-side speaker 26a and the
right-side speaker 26b can be controlled by determining the signal
angle with the reception angle .theta.A instead of the transmission
angle .theta. of the first embodiment.
Note that the respective steps in the flow charts in the present
specification may be performed in a modified execution order, in a
simultaneous manner, or in different execution orders in every
execution, unless the characteristics of the steps are
impaired.
While certain embodiments have been described, these embodiments
have been presented by way of example only, and are not intended to
limit the scope of the inventions. Indeed, the novel embodiments
described herein may be embodied in a variety of other forms;
furthermore, various omissions, substitutions and changes in the
form of the embodiments described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
inventions.
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